Diagnostic differences in respiratory breathing patterns and work of breathing indices in children with Duchenne muscular dystrophy

One-Step Fabrication of Paper-Based Inkjet-Printed Graphene for Breath Monitor Sensors

Irregularities in breathing patterns can be detected using breath monitor sensors, and this help clinicians to predict health disorders ranging from sleep disorders to heart failures. Variations in humidity during the inhalation and exhalation of breath have been utilized as a marker to detect breath patterns, and graphene-based devices are the favored sensing media for relative humidity (RH). In general, most graphene-based RH sensors have been used to explore resistance change as a measurement parameter to calibrate against the RH value, and they are prone to noise interference. Here, we fabricated RH sensors using graphene ink as a sensing medium and printed them in the shape of interdigital electrodes on glossy paper using an office inkjet printer. Further, we investigated the capacitance change in the sensor for the RH changes in the range of 10-70%. It exhibited excellent sensitivity with 0.03 pF/% RH, good stability, and high intraday and interday repeatability, with relative standard deviations of 1.2% and 2.2%, respectively. Finally, the sensor was embedded into a face mask and interfaced with a microcontroller, and capacitance change was measured under three different breathing situations: normal breathing, deep breathing, and coughing. The result show that the dominant frequency for normal breath is 0.22 Hz, for deep breath, it is 0.11 Hz, and there was no significant dominant cough frequency due to persistent coughing and inconsistent patterns. Moreover, the sensor exhibited a short response and recovery time (<5 s) during inhalation and exhalation. Thus, the proposed paper-based RH sensor is promising wearable and disposable healthcare technology for clinical and home care health applications.

Utilising pneuRIP device in determining the adequacy of respiratory support when weaning high-flow nasal cannula in paediatric patients with acute respiratory distress: A pilot study

AIM

Recognition of paediatric respiratory distress and timely intervention is critical, especially during the weaning phase of support in paediatric acute respiratory failure, as weaning too aggressively can lead to further setbacks in a patient's recovery. We aimed to determine if pulmonary function measurements obtained with the pneuRIP device, a noninvasive pulmonary function testing device that provides measurements of labored breathing index (LBI), phase angle and %rib cage (%RC) contribution to breathing, will provide predictive values to assess the adequacy of respiratory support while weaning from HFNC.

METHODS

We reviewed patients ages 0-18 years admitted to the PICU for respiratory distress due to respiratory infections receiving HFNC. Patients with history of chronic lung disease and chronic neuromuscular disease with baseline habnormal breathing patterns were excluded. Phase angle, LBI and %RC were obtained every hour and with every wean of HFNC. Nine patients were enroled.

RESULTS

Mean LBI range remained 1.27-1.68 when LBI was plotted as a function of the HFNC flow rate. Mean values of %RC contribution to breathing ranged 43.65-57.12 as a function of the HFNC flow rate. No significant deviations existed in either %RC (P = 0.16) or LBI (P = 0.16) during the weaning of HFNC. Mean phase angle for all subjects was 41.48°-74.12° for the duration of wean and showed significant deviation from baseline during the weaning process (p = 0.001).

CONCLUSIONS

Measurements of LBI and %RC on the pneuRIP device effectively demonstrated tolerance of weaning HFNC during the recovery phase of acute respiratory failure from a respiratory infection.

Respiratory Inductance Plethysmography to Assess Fatigability during Repetitive Work

Cumulative fatigue during repetitive work is associated with occupational risk and productivity reduction. Usually, subjective measures or muscle activity are used for a cumulative evaluation; however, Industry 4.0 wearables allow overcoming the challenges observed in those methods. Thus, the aim of this study is to analyze alterations in respiratory inductance plethysmography (RIP) to measure the asynchrony between thorax and abdomen walls during repetitive work and its relationship with local fatigue. A total of 22 healthy participants (age: 27.0 ± 8.3 yrs; height: 1.72 ± 0.09 m; mass: 63.4 ± 12.9 kg) were recruited to perform a task that includes grabbing, moving, and placing a box in an upper and lower shelf. This task was repeated for 10 min in three trials with a fatigue protocol between them. Significant main effects were found from Baseline trial to the Fatigue trials (p < 0.001) for both RIP correlation and phase synchrony. Similar results were found for the activation amplitude of agonist muscle (p < 0.001), and to the muscle acting mainly as a joint stabilizer (p < 0.001). The latter showed a significant effect in predicting both RIP correlation and phase synchronization. Both RIP correlation and phase synchronization can be used for an overall fatigue assessment during repetitive work.

Adjustment of high flow nasal cannula rates using real-time work of breathing indices in premature infants with respiratory insufficiency

OBJECTIVE

To assess the feasibility of real-time monitoring of work of breathing (WOB) indices and the impact of adjusting HFNC flow on breathing synchrony and oxygen stability in premature infants.

STUDY DESIGN

A prospective, observational study of infants stable on HFNC. The flow adjusted per predetermined algorithm. Respiratory inductive plethysmography (RIP) noninvasively measured WOB. A high-resolution pulse oximeter collected oxygen saturation and heart rate data. Summary statistics and mixed linear models were used.

RESULTS

Baseline data for 32 infants, final analysis of 21 infants. Eighty-one percent with abnormal WOB. Sixty-two percent demonstrated 20% improvement in WOB. For infants with gestational age <28 weeks, an incremental increase in HFNC flow rate decreased WOB (p < 0.001) and improved oxygen saturation and stability (p < 0.01).

CONCLUSIONS

Premature infants do not receive optimal support on HFNC. The use of a real-time feedback system to adjust HFNC is feasible and improves WOB, oxygen saturation, and oxygen stability. This technology may improve the utility of HFNC in premature infants.

Thoracoabdominal asynchrony and paradoxical motion in Duchenne muscular dystrophy and healthy subjects during cough: A case control study

OBJECTIVE

To assess thoracoabdominal asynchrony (TAA) and inspiratory paradoxical motion at different positionings in subjects with Duchenne muscular dystrophy (DMD) versus healthy subjects during quiet spontaneous breathing (QB) and cough.

METHODS

This is a case control study with a matched-pair design. We assessed 14 DMD subjects and 12 controls using optoelectronic plethysmography (OEP) during QB and spontaneous cough in 3 positions: supine, supine with headrest raised at 45°, and sitting with back support at 80°. The TAA was assessed using phase angle (θ) between upper (RCp) and lower rib cage (RCa) and abdomen (AB), as well as the percentage of inspiratory time the RCp (IP_RCp ), RCa (IP_RCa ), and AB (IP_AB ) moved in opposite directions.

RESULTS

During cough, DMD group showed higher RCp and RCa θ (p < .05), RCp and AB θ (p < .05) in supine and 45° positions, and higher RCp and Rca θ (p = .006) only in supine position compared with controls. Regarding the intragroup analysis, during cough, DMD group presented higher RCp and AB θ (p = .02) and RCa and AB θ (p = .002) in supine and higher RCa and AB θ (p = .002) in 45° position when compared to 80°. Receiver operating characteristic curve analyzes were able to discriminate TAA between controls and DMD in RCa supine position (area under the curve: 0.81, sensibility: 78.6% and specificity: 91.7%, p = .001).

CONCLUSION

Subjects with DMD yields TAA with insufficient deflation of chest wall compartments and rib cage distortion during cough, by noninvasive assessment.

A novel noninvasive approach for evaluating work of breathing indices in a developmental rat model using respiratory inductance plethysmography

Pulmonary function testing (PFT) is an important component for evaluating the outcome of experimental rodent models of respiratory diseases. Respiratory inductance plethysmography (RIP) provides a noninvasive method of PFT requiring minimal cooperation. RIP measures work of breathing (WOB) indices including phase angle (Ф), percent rib cage (RC %), breaths per minute (BPM), and labored breathing index (LBI) on an iPad. The aim of this study was to evaluate the utility of a recently developed research instrument, pneuRIP, for evaluation of WOB indices in a developmental rat model. Sprague Dawley rats (2 months old) were commercially acquired and anaesthetised with isoflurane. The pneuRIP system uses two elastic bands: one band (RC) placed around the rib cage under the upper armpit and another band (AB) around the abdomen. The typical thoracoabdominal motion (TAM) plot showed the abdomen and rib cage motion in synchrony. The plots of phase angle and LBI as a function of data point number showed that values were within the range. The distribution for phase angle and LBI was within a narrow range. pneuRIP testing provided instantaneous PFT results. This study demonstrated the utility of RIP as a rapid, noninvasive approach for evaluating treatment interventions in the rodent model.

Expiratory dysfunction in young dogs with golden retriever muscular dystrophy

Respiratory disease is a leading cause of morbidity in people with Duchenne muscular dystrophy and also occurs in the golden retriever muscular dystrophy (GRMD) model. We have previously shown that adult GRMD dogs have elevated expiratory flow as measured non-invasively during tidal breathing. This abnormality likely results from increased chest and diaphragmatic recoil associated with fibrosis and remodeling. Treatments must reverse pathologic effects on the diaphragm and other respiratory muscles to maximally reduce disease morbidity and mortality. Here, we extended our work in adults to younger GRMD dogs to define parameters that would be helpful in preclinical trials. Tidal breathing spirometry and respiratory inductance plethysmography were performed in GRMD dogs at approximately 3 and 6 months of age, corresponding to approximately 5-10 years in DMD, when clinical trials are often conducted. Expiratory flows were markedly elevated in GRMD versus normal dogs at 6 months. Values increased in GRMD dogs between 3 and 6 months, providing a 3-month window to assess treatment efficacy. These changes in breathing mechanics have not been previously identified at such an early age. Expiratory flow measured during tidal breathing of unsedated young GRMD dogs could be a valuable marker of respiratory mechanics during preclinical trials.